This invention relates to the printing industry, and in particular, to a new and improved cylinder impurity remover apparatus to clean and remove dust and impurities therefrom.
Impurity removers on offset printing presses are known. An example of one is found in U.S. Pat. No. 5,167,189, issued on Dec. 1, 1992 to Phillip W. Jones and is hereby incorporated by reference. During the printing process, ink and water are applied to a plate on a plate cylinder for transferring ink to a blanket on a blanket cylinder and then to paper. Frequently small impurities, clumps of ink, dust or dirt form on the plate cylinder. These irregularities cause unwanted small printing defects commonly known as xe2x80x9chickeysxe2x80x9d to appear on the paper being printed. Several inventions exist directed towards preventing these xe2x80x9chickeysxe2x80x9d from forming on the printed paper.
Numerous problems have existed in preventing these printing irregularities. For example, a printing press is frequently stopped to clean any impurities that form on the printing plate cylinder member. After stopping the printing press, the operator must wipe or apply some force in order to dislodge or remove the dust particle or impurity. Frequently, operators use their own thumb nail to clear the problem. This has several disadvantages. Each time the printing press is stopped for cleaning, the owner and/or operator has lost valuable operation and production time. Further, re-starting is time consuming and an expensive procedure as the initial output of the printing press will produce poor quality print and will continue until the ink and dampening system is at the proper operating balance, sometimes taking several minutes. When impurities form on the plate cylinder, the operator of the printing press must manually clean the components risking bodily injury. This requires the operator to insert his hands and arms into small openings in order to properly clean the cylinder, often risking serious injury. More importantly, the printing machine could be mistakenly turned on which might result in loss of a human limb.
U.S. Pat. No. 5,167,189 is directed at preventing the above problems; however, this apparatus is somewhat difficult to remove for cleaning and maintenance. Further, the operator was required to align the actuator housings and wiper blade to be perfectly parallel to the plate cylinder so as to have a uniform application of the wiper blade to the printing cylinder. This required the operator to periodically check the alignment and readjust the alignment, if necessary. Reaching into confined space to make these adjustments was difficult and potentially dangerous.
The present invention is aimed at improving the ""189 Patent by incorporating fewer parts, by modifying the apparatus to be smaller to allow for usage in various printing presses where space is limited, by re-configuring the apparatus to allow for easy access when maintenance or cleaning is required, and to have a more reliable impurity remover.
In accordance with one aspect of the present invention, a cylinder impurity remover is provided which includes a wiper blade and an actuator bar assembly that is anchored to a printing press frame to temporarily engage the wiper blade with a printing cylinder. During the period of engagement, the printing cylinder is rotating and the wiper blade cleans the rotating surface to remove any impurities that may exist on the printing plate on the cylinder surface.
During operation of the cylinder impurity remover, a pressure supply is provided to the actuator bar, where preferably two parallel piston cylinders (operators) are spaced apart from each other. The piston cylinders are located in blind cylinder chambers or bores that are bored into the actuator bar itself. The actuator bar also houses two parallel reciprocably mounted shafts that hold the wiper blade parallel to the printing cylinder. These are also mounted in bores that extend through the actuator bar next to piston cylinder bores. When a cylinder chamber is pressurized, the piston exerts a forward force on a push block, which is connected to a shaft, causing the shaft to move forward in the direction of the printing cylinder. The shaft is connected to a blade holder and wiper blade which engages with the surface of the printing cylinder. As the forward movement of the shaft occurs, a spring contained in the actuator assembly is compressed. The compressed spring and wiping blade remain in the same position until the fluid pressure supply is discontinued. When the force applied by the fluid pressure supply is stopped, the force from the compressed spring retracts the shaft and wiper blade from the wiping position. This process is periodically repeated in order to maintain a clean and smooth printing surface during the operation of the printing press.
The present invention permits quick and easy removal of the wiper blade assembly for maintenance, cleaning and replacement. The cylinder impurity remover apparatus is installed and removed from the side of the printing press by sliding the actuator bar along a shaped track support which is referred to as a primary support bar. The actuator bar contains a mating slot to engage and align with the support bar. As compared to the prior art, fewer and simpler parts are required. The present invention has fewer parts and simpler parts because the most of the operating components are located in and part of the actuator bar itself and thereby removed as a unit when the actuator bar is slid in and out of the press from the side of the press.
In accordance with another embodiment of the invention, the actuator bar assembly is modified for printing units or stands where there is more space for installation of the impurity remover. This typically occurs at the first printing unit or stand. One end of the actuator bar is connected to the side frame of the press with a hinged support and the other end is docked into another side support on the other side frame of the press. This embodiment permits the actuator bar to be pivoted or swung outward for maintenance or cleaning purposes.